The physics of kicking a soccer ball
The physics behind many sports, including soccer, helps us to
better understand the science involved in the sport and can also help us perhaps
play the sport more efficiently. One of
the key aspects of soccer is the way the ball is kicked. By looking at the kinematics of kicking as
well as taking into account the movement of the layer as they kick the ball, we
can determine the best type of action to create a myriad of desired effects.
That’s the way the ball spins
One aspect of soccer is the spin the ball receives from a kick
that hits the ball off-center. Whenever
a ball comes into contact with a surface that has friction, the ball's
parallel velocity is changed and a torque is applied to the ball by the
off-center force. When the foot comes
into contact with the ball, the upward and forward swing of the leg’s stroke
gives the ball topspin.
This picture
shows the basic concept that is described above. When the ball is at rest, it has no spin and
there is no torque acting on it. Once a
foot impacts with the ball, the reaction force from the collision will cause
the ball to spin in a reverse direction.
Another factor
that can be taken into account when thinking about giving the ball maximum spin
and velocity is the coefficient of friction.
The equation f = mN where f is the frictional
force which is equal to N, the normal force the foot exerts on the ball, and m
is the coefficient of friction, is key in helping us determine how much of the
foot should come into contact with the ball to give it the most spin. The more friction there is between the foot
and the ball, the less the ball will spin after a kick. The coefficient of friction will tell us how
quickly the ball will travel through the air.
As the ball gains speed, the spin of the ball will also increase. We can see from this equation that an
increase in coefficient of friction gives the ball less spin. To get the most spin out of the ball, the
ball must be kicked slightly away from its center of gravity, giving less time
for the foot to come into contact with !
the ball, producing
more power exerted on one centralized area of the ball, and therefore
increasing the overall spin and velocity of the ball. This is one of the factors that causes a kicked ball to curve in the air. When kicking a ball straight on so that the
foot hits the balls center of gravity, the ball will go straight.
Some other
factors that must be taken into account when kicking a ball is the pressure on
the ball, the initial velocity of the ball, and the speed of the foot as it kicks
the ball. The way the human body moves,
however, is not very predictable so the force of the leg as it swings towards
the ball is a variable factor. The
kicking that is discussed here takes into account that the ball is at rest when
it is kicked.
LINKShttp://www.phys.washington.edu/~wilkes/post/temp/phys208/volume4.htmlhttp://physicsweb.org/article/world/11/6/8http://www.oceansiderevolution.com/EINSTEIN_4.htm HOME